scholarly journals ULF waves excited by negative/positive solar wind dynamic pressure impulses at geosynchronous orbit

2010 ◽  
Vol 115 (A10) ◽  
pp. n/a-n/a ◽  
Author(s):  
X. Y. Zhang ◽  
Q.-G. Zong ◽  
Y. F. Wang ◽  
H. Zhang ◽  
L. Xie ◽  
...  
Keyword(s):  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Geosynchronous Orbit ◽  
Ulf Waves

Ultra-Low Frequency (ULF) waves originating in solar wind dynamic pressure oscillations and propagating through the magnetosheath to the inner magnetosphere

2020 ◽  
Author(s):  
Marina Georgiou ◽  
Christos Katsavrias ◽  
Ioannis Daglis ◽  
Georgios Balasis
Keyword(s):  
Solar Wind ◽  
Wavelet Transform ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Slow Solar Wind ◽  
Ulf Waves ◽  
Pressure Oscillations ◽  
Inner Magnetosphere ◽  
Cross Wavelet ◽  
Wave Properties

<p>Several observational studies have shown that ULF oscillations of the solar wind dynamic pressure can drive periodic fluctuations in magnetic field measurements at corresponding frequencies. In this study, we use multi-spacecraft (Cluster, GOES, THEMIS and Van Allen Probes) mission measurements to investigate the propagation of pressure fluctuations-driven pulsations within the Pc5 and Pc4 frequency range (from ~0.5 to 25 mHz) into the magnetosphere. During intervals of slow solar wind — to exclude waves generated by velocity shear at the magnetopause — common periodicities in electromagnetic fields in the magnetosphere and the solar wind driver are first detected in Lomb-Scargle periodograms. Then, using the cross-wavelet transform, we examine the causal relationship and specifically, in cross-wavelet spectra and wavelet transform coherence. Lastly, spatial and temporal variations of wave properties are mapped from beyond the magnetopause to the inner magnetosphere through frequency, polarisation and power signatures of waves detected at the various probes. The observed dependence of wave properties on their localisation offers an excellent source for verification of the role that solar wind dynamic pressure oscillations as driver of ULF waves propagating through the magnetosheath into the dayside and nightside magnetosphere.</p>

scholarly journals Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model

2012 ◽  
Vol 30 (8) ◽  
pp. 1285-1295 ◽  
Author(s):  
T. R. Sun ◽  
C. Wang ◽  
N. L. Borodkova ◽  
G. N. Zastenker
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Model ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Geosynchronous Orbit ◽  
Total Field ◽  
Fast Solar Wind ◽  
Dominant Component ◽  
Mhd Simulations

Abstract. We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (Pd) enhancements. Taking three Pd enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component Bz can be efficiently predicted by the MHD model. The predicted B and Bz varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., Bx and By). In contrast, the limitations of T01 model in predicting responses to fast Pd enhancements are presented.

Solar wind dynamic pressure enhancements and polar auroras

1998 ◽  
Vol 22 (9) ◽  
pp. 1305-1308 ◽  
Author(s):  
Y Zhang ◽  
D.J McEwen ◽  
I Oznovich
Keyword(s):  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure
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